1. Field of Invention
The present invention is directed to an eccentrically-shaped plug members for use with seats disposed within a tubular member for restricting fluid flow through tubulars disposed within oil and gas wells and, in particular, to eccentrically-shaped plug members that permit a consistent inner diameter through two or more seats.
2. Description of Art
Seats disposed within oil and gas wellbores for landing a plug member to restrict flow through the wellbore are generally known in the art. For example, typical seats are disposed on a tubular member have a bore or passageway that is restricted by the seat. The plug element, such as a ball or dart, is disposed on the seat, preventing or restricting fluid from flowing through the bore of the seat and, thus, isolating the tubing or conduit section in which the seat is disposed. As force is applied to the plug member, the conduit can be pressurized for tubing testing or tool actuation or manipulation, such as in setting a packer. Seats are also used in cased hole completions, liner hangers, flow diverters, frac systems, and flow control equipment and systems.
In a tubular having multiple seats, the inner diameter opening through the seat decreases in size as the seat is located lower down the tubular. For example, in a tubular having three seats, the lowermost seat comprises an inner diameter that is smaller than the inner diameter of the seat located above the lowermost seat. Similarly, the uppermost seat has an inner diameter that is larger than the inner diameters of the seats located below the uppermost seat. This variation in the inner diameters is so that a plug element can pass through the seat(s) above to land on the seat below.